Pro Investor Academy
LESSON 3.6
5 min learning time

Building Portfolios With ETFs

Many long-term investors hold broad funds as a base and add researched companies deliberately.

The short answer

A common structure is to treat a broad, diversified fund as the base of a portfolio and add individually researched companies on top of it as a deliberate, sized decision. Doing this without checking overlap can quietly concentrate a portfolio far more than the position sizes alone suggest.

Learning objectives

  • Build a simple portfolio from a few ETFs with distinct jobs
  • Calculate weighted overlap: how much of one company you hold across several funds
  • Weigh added complexity against genuinely new diversification

A common structure

Broad funds provide diversified ownership without requiring per-company research. Individual companies require research and add concentration.

Treating funds as the base and individual holdings as deliberate additions makes concentration a choice rather than an accident.

Be honest about overlap

If a broad U.S. fund already places large weight in a company, adding a large individual position in that same company concentrates you far more than the position size suggests. A 5% individual position added to a fund that already holds 7% of that same company in its own weighting is not simply a 5% addition to your exposure.

This is education, not allocation advice

Study explains structures. It does not tell you what percentage to put anywhere, and this platform never produces portfolio allocations.

Combining several ETFs

Give each fund one job, such as broad U.S. stocks, international stocks, or bonds. If two funds do the same job, you mostly add overlap and paperwork.

Weighted overlap tells you your real exposure. Multiply each fund's weight in your portfolio by the company's weight inside that fund, then add the results.

Hypothetical example: 60% in Fund A, where Company X is 5% of the fund, and 40% in Fund B, where Company X is 10%. Exposure = 0.60 × 5% + 0.40 × 10% = 3% + 4% = 7% of the whole portfolio in Company X.

  • List each fund's job in one line. Drop or merge funds that share a job.
  • Check the top holdings of each fund and calculate weighted overlap for the largest names.
  • Compare total costs: each fund's expense ratio, weighted by how much you hold.
  • Fewer, complementary funds are easier to understand and rebalance. More funds is not automatically more diversification.

Key concepts

Select a term to read its definition.

  • Core holding

    A broad, long-term position meant to form the base of a portfolio, as distinct from smaller positions around it.

    View in the glossary
  • Concentration risk

    Risk created when too much of your outcome depends on one holding, sector or theme.

    View in the glossary
  • Overlap

    When two funds own many of the same securities, so holding both adds less diversification than it appears to.

    View in the glossary
See the full glossary

Why this matters

Structure decided in advance survives contact with a volatile market.

Check your understanding

No score is recorded. This is only here to test whether the lesson landed.

1. An investor holds a broad U.S. market ETF and adds a second ETF that tracks the largest U.S. companies. What is the most important thing to check first?
2. True or false: combining more ETFs always produces a simpler, easier-to-manage portfolio.
3. A hypothetical investor wants global stock exposure and considers either one broad global ETF or five separate regional and sector ETFs. What does this level's material suggest they weigh?

0 of 3 answered. Answer every question to see the answers.

Key takeaways

  • A fund can serve as a diversified base while individual holdings are added deliberately
  • Overlap between a fund's existing weighting and a new individual position compounds true exposure
  • This platform describes structures and never generates a personal allocation

Related concepts

Written by
Pro Investor Academy Research Team
Content type
Educational article
Published
2026-09-13
Last reviewed
2026-09-13

Sources

Tracking and ETF QualityWhat Crypto Assets Are

Educational content only. This lesson is not investment, tax or legal advice and does not recommend buying or selling any specific investment. All investing involves the risk of loss.